Voltage comparator circuit

Inactive Publication Date: 2005-12-15
RENESAS ELECTRONICS CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0076] According to the present invention, high-speed operation is achieved by a simple structure comprising an input differential stage, a folded cascode differential stage, and first and second current mirror circuits disposed oppositely between power sources.
[0077] According to the present invention, high-speed operation is made possible by having the first and second current mirror circuits with a current amplification function and increasing the driving ability as a result.

Problems solved by technology

As a result, the power consumption will be increased as well.
Also, since the waveform of the output terminal cannot be swung to the full voltage, the N-channel MOS transistor and P-channel MOS transistor of the inverter connected at a later stage of this voltage comparator circuit are turned on simultaneously and a through current flows, resulting in an increase in power consumption.
As a result, the power consumption is increased.
Further, one of the reasons why the output terminal waveform cannot be swung to the full voltage is because the transistors are vertically stacked.

Method used

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Examples

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embodiment

[0091]FIG. 1 is a drawing showing an equivalent circuit of a differential amplifier of a first embodiment according to the present invention. It is a differential amplifier used in a voltage comparator circuit with a noninverting input and an inverting input. In reference to FIG. 1, the differential amplifier of the first embodiment comprises a first differential pair of a first P-channel MOS transistor MP1 and a second P-channel MOS transistor MP2 with their sources connected in common, a second differential pair of a first N-channel MOS transistor MN1 and a second N-channel MOS transistor MN2 with their sources connected in common, third and fourth N-channel MOS transistors MN3 and MN4 with their gates connected in common to a first voltage source (V1), third and fourth P-channel MOS transistors MP3 and MP4 with their gate connected in common and their sources connected in common to a positive power source (VDD), a fifth and sixth P-channel MOS transistors MP5 and MP6 with their g...

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PUM

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Abstract

A voltage comparator that realizes high-speed operation with a simple structure includes an input differential stage having a first differential pair and a second differential pair, into which a differential voltage is inputted from differential input terminals In+ and In−, with reverse polarity to each other, folded cascode-type differential stages, which adds a differential output signal of the first differential pair and a differential output signal of the second differential pair and is connected to a differential output of the input differential stage, and oppositely disposed first and second current mirror circuits, which receive differential outputs of the folded cascode-type differential stages into their respective inputs, with reverse polarity to each other and their outputs connected in common to an output terminal. The folded cascode-type differential stage adds the differential output signal of the first differential pair and the differential output signal of the second differential pair.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a differential amplifier and a voltage comparator circuit using the same, especially to a voltage comparator circuit suitable for a high-speed differential interface circuit. BACKGROUND OF THE INVENTION [0002] In recent years, high-speed differential interface circuits are used in various types of devices. For instance, in the field of TFT_LCD (Thin Film Transistor Liquid Crystal Display), as interfaces between LCD driver LSI and timing controller LSI, RSDS (Reduced Swing Differential Signaling: a registered trademark of National Semiconductor Corporation) and mini-LVDS (mini Low Voltage Differential Signaling: a registered trademark of Texas Instruments, Inc.) are becoming standardized. The voltage comparator circuits with differential inputs are used in the receiver circuits of these technologies. [0003] The frequencies of the differential signal inputted into the voltage comparator circuits are approximately 85 MHz an...

Claims

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Application Information

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IPC IPC(8): H03K5/08H03F1/22H03F3/45H03K17/30
CPCH03F3/45192H03F3/45219H03F2203/45248H03F2203/45366H03F2203/45644H03F2203/45651
InventorNISHIMURA, KOUICHI
OwnerRENESAS ELECTRONICS CORP